Some fungal-farming ants are loyal to their crops

A group of fungi-farming ants are not only loyal to particular species of fungus, the relationship is so close it appears the ants and the fungus may be evolving together, a new study indicates.

Each species of farming ants exclusively grows a particular species of fungus to feed their colony, even when the ants' nests are spread as far apart as Costa Rica, Panama or Ecuador, said the researchers, who calculated that the oldest of these relationships traces back more than 5 million years.